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Today I found out that I actually found a Linux kernel bug.
Okay, that's pretty click-baity. I did not find it, I tripped over it. But anyway: Look at me, I'm a hacker now! ๐
Today I found out that I actually found a Linux kernel bug.
Okay, that's pretty click-baity. I did not find it, I tripped over it. But anyway: Look at me, I'm a hacker now! ๐
What happened?
I recently installed the new 6.1 Linux kernel on my work machine (oh, yes, I have a Linux machine at work).
A little program I use to simulate HDL code (hardware description language) called GHDL would work all fine on the old kernel (5.15ish).
Suddenly, it would not work anymore blurting out a SEGFAULT on a really basic task.
So, I raised an issue with the GHDL project, lining out what happened.
๐ https://github.com/ghdl/ghdl/issues/2359
A certain `tgingold` helped me getting more info using a debugger (yeah, the initial toot really was clickbait ๐ I would've never figured out how to find the particular problem).
A few messages forth and back later, it turns out, an issue with `mremap` in the Linux kernel caused the crash.
How? Well, apparently `mremap` had an issue that was fixed some time recently. But the function would now not work as it did before (when fixing one bug causes another).
If I'm not mistaken, it was CVE-2022-41222.
So that got quietly fixed in a minor update shipped out recently by Ubuntu. So, one morning (specifically yesterday morning), the problem was gone #magic.
So, yeah, #FileBugReports. Be specific and try to line the problem out as clearly as you can. You can help #OpenSource #FOSS and make software better. So: You, too, can be a hacker. ๐